The Romans expected to conquer Carthage.

The correct answer is: C. It was expected by the Romans that they would conquer Carthage.

The other options are incorrect because they do not accurately reflect the meaning of the sentence.

• Option A: Carthage was expected to be conquered by the Romans. This option is incorrect because it does not specify who expected Carthage to be conquered. The sentence does not say that Carthage was expected to be conquered by anyone, only that the Romans expected to conquer Carthage.
• Option B: The Romans were expected to conquer Carthage. This option is incorrect because it does not specify who expected the Romans to conquer Carthage. The sentence does not say that the Romans were expected to conquer Carthage by anyone, only that the Romans expected to conquer Carthage.
• Option D: The Romans expected to have conquered Carthage. This option is incorrect because it does not accurately reflect the tense of the sentence. The sentence is in the simple future tense, which indicates that the Romans expected to conquer Carthage in the future. Option D, on the other hand, is in the perfect tense, which indicates that the Romans expected to have conquered Carthage in the past.

Therefore, the correct answer is: C. It was expected by the Romans that they would conquer Carthage.